One of the disadvantages of the FRAM memory technology is that each read access to the memory contents destroys the stored information in the memory cells. Therefore, the data that is read from memory cells needs to be written back into memory cells after each read access in order to restore their original content. This write operation is referred to as write-back. It is to be ensured under all circumstances, as for examples shorts on the supply pins of the FRAM memory device, that a complete write-back operation can be performed. Otherwise, the integrity of the FRAM memory is affected. However, in order to perform a complete write-back operation, the power supply system has to maintain a required supply voltage level for the FRAM memory during the event of power failure until the write-back operation is finished.